Extendible structures are extensively used as portable towers and booms. They are collapsible to be stored in envelopes of lesser height or length, and can be extended (deployed, erected) to a greater height or length. Such structures most frequently require cables or other axially-operated systems to extend them to their full length, and locking means to hold them in their extended condition. Especially for airborne and space vehicles, where such structures find frequent employment, these are not only additional complications subject to malfunction, but represent undesirable weight. For land-based use, such as for towers to support antennae, they represent undesirable ground weight and resistance to the wind.
It is an object of this invention to provide an extendible structure which is inherently biased towards its extended configuration, and which requires no locking elements to hold it extended.
Furthermore, the integrity of such structures when damaged or disabled is a serious matter, especially when the structure is deployed where it can be repaired only with difficulty, or where it may not be repairable at all.
It is an object of this invention to provide an extendible structure which can be damaged or fractured to a substantial extent, and still retain substantial integrity.